Pipe inside cleaning device

ABSTRACT

Apparatus for cleaning the inside surface of a tubular workpiece such as a pipe by blasting the workpiece surface with an abrasive slurry. The slurry is impelled by a gas supplied by a mechanism designed to impart a pulsating pressure to the blasting nozzle. One disclosed embodiment of the invention utilizes a mechanical rotary valve combined with an accumulator and another embodiment utilizes a reciprocating piston for imposing a relative high pressure onto a quantity of impelling gas and then suddenly releasing it to the blasting nozzle.

United States Patent [191 Kobayashi 1 Oct. 28, 1975 PIPE INSIDE CLEANING DEVICE [75] Inventor: Shigeharu Kobayashi, Shizuoka,

Japan [73] Assignee: 'Fuji Seiki Machine Works, Ltd.,

Shizuoka, Japan [22] Filed: Sept. 20, 1974 [21] Appl. No.: 507,764

[52] US. Cl. 15/35; 51/12 [51] Int. CI. B24C 3/32 [58] Field of Search 15/3.5, 3.51; 51/8 R, 12, 51/15; 128/66; 222/3 [56] References Cited UNITED STATES PATENTS 2,696,049 12/1954 Black 51/12 X 3,109,262 11/1963 Weaver 51/8 R 3,299,459 1/1967 McCune 51/8 R X 3,427,763 2/1969 Maasberg 51/15 X 3,771,517 11/1973 Radecki ..128/66 3,783,867 1/1974 Summersby l28/66X Primary ExaminerDonald D. Kelly Attorney, Agent, or FirmWoodhams, Blanchard and Flynn [5 7] ABSTRACT Apparatus for cleaning the inside surface of a tubular workpiece such as a pipe by blasting the workpiece surface with an abrasive slurry. The slurry is impelled by a gas supplied by a mechanism designed to impart a pulsating pressure to the blasting nozzle. One disclosed embodiment of the invention utilizes a mechanical rotary valve combined with an accumulator and another embodiment utilizes a reciprocating piston for imposing a relative high pressure onto a quantity of impelling gas and then suddenly releasing it to the blasting nozzle.

7 Claims, 2 Drawing Figures PIPE INSIDE CLEANING DEVICE FIELD OF THE INVENTION V The invention relates to a method and apparatus for utilizing a wet abrasive slurry to cleanthe inside ofa tubular workpiece and means for blasting same into the inside of such workpiece, such as a pipe, and doing so at a pulsating intensity.

BACKGROUND OF THE INVENTION It has long been known to utilize an abrasive slurry impelled by a gas under pressure, usually air, for cleaning the inside of a tubular workpiece, such as a pipe. In such equipment it is conventional to provide an elongated venturi tube with a nozzle at the throat thereof for introducing the blasting gas into a stream of abrasive slurry. The pipe to be cleaned is fixed at the end of and coaxially with the venturi tube and receives the blasting mixture thereinto. This is effective but it is time consuming, the operation often taking as much as minutes for cleaning the inside of a pipe to a desirable degree of finish.

Accordingly it is desirable to provide a method, and an apparatus for carrying out such method, by which an effective job of cleaning can be accomplished, same being to the same high degree of quality as was obtainable by previous methods, and yet substantially to reduce the amount of time required.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an schematic diagram of one form of an apparatus embodying the apparatus aspects of the invention and appropriate for carrying out the method aspects of the invention.

FIG. 2 is a diagrammatic illustration of another form of apparatus embodying the apparatus aspects of the invention and capable of carrying out the method aspects thereof.

SUMMARY OF THE INVENTION The method aspects of the invention contemplate supplying the impelling gas to the slurry in a pulsating pattern, namely a continuous flow of gas under a manual pressure with intermittent pulses of gas under a higher pressure. This quite unexpectedly greatly increases the turbulence of the slurry in the pipe being cleaned and correspondingly and unexpectedly greatly selves, are insofar as the method is concerned only two illustrations of many appropriate forms of such apparatus. i

Turning now to FIG. 1 there is shown a conventional venturi tube 1 having a throat 2 and a supply conduit 3 which is connected to a suitable supply of an abrasive slurry. Said slurry may be of any conventional kind, such as a suitable solid grit carried in a liquid carrier such as water. The tubular workpiece, here a pipe, to be cleaned is indicated at W and same is connected by any convenient and conventional fitting coaxially to the discharge end of the venturi tube 1.

Positioned concentrically within said venturi tube 1 and shortly past the throat 2 in any conventional manner is a nozzle 6 for the introduction thereinto of the impelling gas, such as compressed air. The nozzle itself is conventional and hence needs no detailing. The nozzle is supplied from a source of pressure P into a conincreases the rapidity by which the cleaning operation DETAILED DESCRIPTION Inasmuch as the method aspect of the invention can be best understood by consideration of the apparatus by which same is carried out, attention will be directed toward the apparatus embodying the invention with the understanding however that the two forms of apparatus herein specifically disclosed are only two of many possible devices by which method aspects of the invention may be carried out and, though inventive in themduit 7 to a rotary valve 8. Said valve is operated by a motor 9 energized from any convenient source not shown. The gas flows from-the rotary valve 8 through a further conduit 11 into an accumulator 12 from which it flows through a check valve 13 and into a pipe 14 leading to a nozzle 6.

The volume of the accumulator is selected in relation to the quantity of impelling gas passing therethrough such that it will convert the essentially square wave pulses of gas in the rotary valve into somewhat more smoothly modulated pulsations of compressed air supplied through the nozzle 6. Further and preferably the accumulator 12 is also so designed as to keep sufficient gas flowing continuously through the nozzle 6 and venturi tube as to prevent the solids in the slurry from settling and clogging the equipment. Thus the output of the nozzle 6 is continuous with a plurality of peak pulsations which keeps the gas flowing continuously through the nozzle and pipe to be cleaned but with sufficient pressure peaks'as to maintain the abrasive slurry within said pipe in a high degree of agitation. Thus the cleaning operation carried out very quickly and with a high level of quality.

With respect to FIG. 2 there is shown a similar venturi tube, throat, supply conduit and nozzle which is identical to that described in connection with FIG. 1 and therefore needs no further description. Likewise the pipe W is again fitted onto the end of the venturi tube 1 by a suitable fitting 4.

In this embodiment pressure is supplied from a source P through a conduit 16 into branches l7 and 18. The branch 18 passes through a check valve 19 into a small chamber 21 in the small end 22 of the stepped cylinder 23 described further hereinafter. From the small chamber 21 a conduit 24 leads through the ports 26 of a four-way valve 27 to a conduit 28 and thence to the supply line 14 of the nozzle 6.

The stepped cylinder 23 comprises serially arranged sections 31, 32 and 22 of three different diameters as shown. Within said cylinders 31 and 32 there is located a first piston 34 of relatively large diameter and a second piston 36 of relatively small diameter, the two being connected by a rod 37.

The above mentioned branch 17 connects to the inlet port of a magnetic valve 41 whose outlet port connects to a conduit 42 leading to the chamber 30 within the large section 31 of the stepped cylinder 33. A further conduit 43 leads from said chamber 30 through a further magnetic valve 44 to the low pressure side of the pressure system, such as atmosphere indicated at A. Appropriate circuitry 46 energized from any convenient source S-l is connected to operate the two valves 41 and 44, preferably simultaneously.

A conduit 47 extends from the chamber 30 to the ports 48 of the magnetic valve 27 and thence to a junction point 49 for connection to the conduit 28.

This then provides two basic paths of flow for pressure gas originating at P and flowing to the nozzle 6, namely, one line utilizing branch 18 and the parts connected thereto and the other branch utilizing line 17 and the parts connected thereto.

In operation, the source 8-1 which will normally be a suitable timer will close the valve 41 and open the valve 44. Likewise the source 8-2 which may be further contacts of the same timer will close the ports 48 and open the ports 26. Thus air will flow through the check valve 19 into and through the chamber 21, thence through the ports 26 and into the nozzle 6. This will effect a blast of impelling gas into the slurry within the venturi to cause a flow thereof in the usual manner to the interior of the pipe W to be cleaned.

At the same time the gas flowing into the chamber 21 will drive the piston 36 upwardly and since the valve 44 is open to the atmosphere same will move substantially to the top of the chamber 30 although, if desired, a quantity of trapped gas may be provided in the upper end thereof to prevent said piston 34 from striking the end of the cylinder. After a predetermined period of time, which will normally be only a few seconds, the source S-l changes and the magnetic valves 41, 44 and 27 change their position, valve 41 now being open, valve 44 now being closed, ports 26 being closed and ports 48 open. The pressure gas now flows through the branch 17 and conduit 42 into the cylinder 30 and with the ports 48 open it flows onto the nozzle 6. This continues the supply of gas to the nozzle and simultaneously develops a pressure within the chamber 30 which, acting upon the relatively large piston 34, generates sufficient force to drive the relatively small piston 36 downwardly. This compresses the gas in the chamber 21 to a magnitude of compression substantially above that of the source P since ports 26 are closed and the check valve 19 prevents reverse flow from the chamber 21 to the conduit 18. The source S-2 now changes to close ports 48 and open ports 26. This permits flow from the chamber 21 through the conduit 24 into the conduit 28 and thence to the nozzle 6. Thus a burst of gas at high pressure exits from the nozzle 6 but again due to the characteristics by which pressure is expelled from the chamber 21 the pressure pattern exiting from the nozzle 6 is a smoothly modulated pulse rather than an abrupt square wave pulse.

The source 8-] now returns to its original condition which closes valve 41 and opens valve 44. Thus flow returns to the branch 18 and parts connected thereto and the upper end of the chamber 30 returns to its initial low pressure. Pressure fluid again enters into the chamber 21 driving the piston 36 upwardly and the cycle repeats.

As in the apparatus of FIG. 1, the intermittent supply of impelling gas through the nozzle 6 into the slurry causes an extremely high level of turbulence within the type W and thereby causes a highly effecting cleaning operation and one which is much more rapid than in previously known systems.

Although a particular preferred embodiment of the invention has been disclosed above for illustrative purposes, it will be understood that variations or modifications thereof which lie within the scope of the appended claims are fully contemplated.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An apparatus for utilizing an abrasive slurry for cleaning the inside of a tubular workpiece, such as a pipe, and having a nozzle for introducing a supply of impelling gas such as air into an abrasive slurry for directing same under pressure and with a high degree of turbulence into the interior of said tubular workpiece, the improvement in means for supplying said impelling gas comprising;

means for supplying gas under pressure to said nozzle at a constant minimum value and including means for intermittently raising said pressure.

2. The device of claim 1 wherein said means for raising said pressure does so at a smoothly modulated curve for both the ascending side of the pressure pulse and the descending side thereof.

3. The device of claim 2 wherein said means for raising said pressure comprises an intermittently open and closed valve and an accumulator, the pressure source feeding said impelling gas through said valve into said accumulator and the gas flowing out of said accumulator to said nozzle, the volume of said accumulator being so correlated to the volume of flow of said gas that there is a constant flow of gas therethrough with pressure peaks at the outlet thereof corresponding to the open positions of said valve.

4. The device of claim 3 wherein said intermittently open and closed valve is a rotary valve.

5. The device of claim 1 including a source and conduit means supplying impelling gas from said source to said nozzle, accumulating means for accumulating gas and supplying same into said conduit means as a pulse at a higher pressure than the normal pressure within said conduit means.

6. The device of claim 1 including a source of gas under pressure and first conduit means for conducting same from said source to said nozzle;

an accumulator for accumulating a quantity of said gas; piston means including force magnification means; and gas pressure means intermittently operable for energizing said piston means to impel a pulse of gas from said accumulating means into said conduit means.

7. The device of claim 1 including conduit means for conducting impelling gas from a source of pressure to said nozzle;

a chamber having a first diameter and said conduit means connected thereto so the gas flowing through said conduit means will also fill said chamber;

a check valve preventing flow of gas from said chamber back toward said source;

pressure responsive means including a cylinder and piston of diameter larger than that of said chamber; and

conduit and valve means deriving pressure from said source and intermittently supplied to said cylinder;

whereby gas so supplied to said cylinder will create a force therein of sufficient magnitude to actuate said piston to create in said first chamber a pressure in excess of the pressure of said source and drive a pulse of gas from said chamber into said conduit and thence to said nozzle. 

1. An apparatus for utilizing an abrasive slurry for cleaning the inside of a tubular workpiece, such as a pipe, and having a nozzle for introducing a supply of impelling gas such as air into an abrasive slurry for directing same under pressure and with a high degree of turbulence into the interior of said tubular workpiece, the improvement in means for supplying said impelling gas comprising; means for supplying gas under pressure to said nozzle at a constant minimum value and including means for intermittently raising said pressure.
 2. The device of claim 1 wherein said means for raising said Pressure does so at a smoothly modulated curve for both the ascending side of the pressure pulse and the descending side thereof.
 3. The device of claim 2 wherein said means for raising said pressure comprises an intermittently open and closed valve and an accumulator, the pressure source feeding said impelling gas through said valve into said accumulator and the gas flowing out of said accumulator to said nozzle, the volume of said accumulator being so correlated to the volume of flow of said gas that there is a constant flow of gas therethrough with pressure peaks at the outlet thereof corresponding to the open positions of said valve.
 4. The device of claim 3 wherein said intermittently open and closed valve is a rotary valve.
 5. The device of claim 1 including a source and conduit means supplying impelling gas from said source to said nozzle, accumulating means for accumulating gas and supplying same into said conduit means as a pulse at a higher pressure than the normal pressure within said conduit means.
 6. The device of claim 1 including a source of gas under pressure and first conduit means for conducting same from said source to said nozzle; an accumulator for accumulating a quantity of said gas; piston means including force magnification means; and gas pressure means intermittently operable for energizing said piston means to impel a pulse of gas from said accumulating means into said conduit means.
 7. The device of claim 1 including conduit means for conducting impelling gas from a source of pressure to said nozzle; a chamber having a first diameter and said conduit means connected thereto so the gas flowing through said conduit means will also fill said chamber; a check valve preventing flow of gas from said chamber back toward said source; pressure responsive means including a cylinder and piston of diameter larger than that of said chamber; and conduit and valve means deriving pressure from said source and intermittently supplied to said cylinder; whereby gas so supplied to said cylinder will create a force therein of sufficient magnitude to actuate said piston to create in said first chamber a pressure in excess of the pressure of said source and drive a pulse of gas from said chamber into said conduit and thence to said nozzle. 